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What is that little "weep hole" on the bottom of my water pump?


MarcDeSoto
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I'm trouble shooting cooling system leaks on my 48 Desoto before I start the engine.  Finally stopped the leaks at the water pump to radiator hoses.  but I'm still getting a very small leak that seem to come from a tiny weep hole.  What is the weep hole for, and is it supposed to leak a little bit?  

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A "weep hole" is exactly what it is. It's purpose is to allow radiator water a place to escape once the shaft bushing goes bad.

 

Some old water pumps come with either a grease fitting already installed to grease the bushing,and I guess some come with just a plug screwed into the hole for the grease plug. If that is the case,you need to remove the plug,screw a grease fitting in where the plug was,and grease it before you run the engine any more.

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This water pump is a rebuilt unit I bought in the 80s.  It has never run on an engine before.  I have the plug installed instead of the grease fitting.  Is the grease fitting a 1/4" npt fitting?   Is it normal for the weep hole to leak coolant on a good water pump?  Are the water pumps sold on Ebay and AB good quality pumps?  

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4 hours ago, MarcDeSoto said:

This water pump is a rebuilt unit I bought in the 80s.  It has never run on an engine before.  I have the plug installed instead of the grease fitting.  Is the grease fitting a 1/4" npt fitting?   Is it normal for the weep hole to leak coolant on a good water pump?  Are the water pumps sold on Ebay and AB good quality pumps?  

Which means you have never greased the bushing in the water pump shaft,which also probably means your water pump now needs to be rebuilt.

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Posted (edited)

Why would it need to be rebuilt?  Wouldn't the rebuilder put some grease in there?  It turns over fine.  The water coming out of the weep hole looks brown.  Maybe it's the grease?  

Edited by MarcDeSoto
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I went through my water pump when I rebuilt the engine back in 1980 or 81, and have yet to run the engine.  The water pump is now froze up.  And it was adequately greased, and I have never put water in the engine.  I suspect some little critters are the cause (probably "mud dobbers"), but haven't pulled the water pump back off yet to see what's going on there.

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The leak cause is dependent of the rebuild method.  Some rebuilders use the original type bushing and seal.  Others may upgrade to a needle bearing and different seal.   Do you have access to that info??  If it has no zerk, it may have been upgraded and the new seal is not seated, if it is a face to face type.   But, it wouldn't hurt to add a zerk, give it a shot of grease and run it a bit.  

 

Edit:  was your old one rebuilt and returned, or was it an exchange rebuilt.  If exchange you may have a newer pump with the bearing and new type seal as part of the new core.

Edited by kencombs
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I can't remember if my water pump was rebuilt or I got an exchange since it was about 40 years ago, but I think it was the latter!  My water pump turns perfectly with no play.  So I'll put a zerk fitting in and grease it with water pump grease, if they still sell such a thing.  

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That's where my plug is.  I'm going to try to find a zerk fitting for it.  Does your pump still work OK, or are you going to buy a new one?  I guess it's a good idea to buy one as an extra to carry in trunk in case the pump has a break down.  I don't think the local garage would have these pumps available in stock!

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2 minutes ago, MarcDeSoto said:

That's where my plug is.  I'm going to try to find a zerk fitting for it.  Does your pump still work OK, or are you going to buy a new one?  I guess it's a good idea to buy one as an extra to carry in trunk in case the pump has a break down.  I don't think the local garage would have these pumps available in stock!

The original was a 2 rotor type.  I bought a new one but it has an extra hole on the back plate for the external bypass, which I don't have.  Wasn't expensive. I'm going to use the original back plate, extra to me already blocking the hole off in the block.

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Does yours have the heater hose bypass on top?  I'm buying a new water pump on ebay.  It doesn't have the zerk fitting because it says it has a sealed bearing with no maintenance.  

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1 hour ago, capt den said:

i thought you could use wheel bearing grease in the water pump zerk.     capt den

In the old days you used a special water pump grease. I believe its prime quality was that it would resist being washed out by water if the seal was not perfect.

 

I think chassis grease might be a better match than old fashioned wheel bearing grease. Old fashioned wheel bearing grease is “high fiber”. Not fiber in the sense of actual fibers but in the sense that it is sticky and stringy which helps it adhere to the rotating ball or roller bearings. Our old water pumps use bushings (“plain bearings” in engineering speak) rather than roller or ball bearings and I suspect the stringiness of wheel bearing grease may not be good at providing lubrication in that environment. Chassis lubricants seem to be designed for sliding and rubbing surfaces which is why I think it might be a better replacement for water pump grease.

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13 hours ago, MarcDeSoto said:

Does yours have the heater hose bypass on top?  I'm buying a new water pump on ebay.  It doesn't have the zerk fitting because it says it has a sealed bearing with no maintenance.  

Not at home for a while so I'll have to check next week.

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